Lump on the beginning of the left lesticle

Patient: Hey doctor,i’m 23 years old, 180 cm height and 85 km weight.I’ve figured out new lump at the beginning of my left testicle, I think at epididymis,i’ts size start growing when i was in 15 years and still growing for now.what should i do, is it a good thing or a bad thing ?note the testicle surface is very good so soft no other lumps or anything, I’ve great sex life, everything is going OK, tell me about it? and what should i do i’m so concerned ?

Symptoms: just lump on testicle